Flash lamp



March 26, 1935.

C. J. NICHOLS 'FLASH LAMP Filed April 18, 1932 ,fizvenior Patented Mar. 26, 1935 I I I p UNITED STATES PATENT OFFICE FLASH LAMP Cheshire Jones Nichols, Cleveland, Ohio Application April 18, 1932, Serial No. 605,989

' Claims. (Cl. 6731) This invention relates to flash lamps of the the gaseous mixture enclosed in the lamp may enclosed type and has for its object an inexpenbe ignited by applying sufficient induction voltsive and safe lamp especially for photographic age to the base contacts to cause a spark or disusage. charge inside the envelope.

5 .Metallic foils and wire have been mentioned in It is well known that a gaseous mixture may 5 this connection as usable with oxygen gas atmosbe ignited by many other methods. These methphere at sub-atmospheric pressures. Metallic ods may be used in connection'with the described powders mixed with a solid oxidizing agent in lamp. For example, causing a spark or disvacuo represent another variation of the precharge inside the envelope by applying an elecvious art. Ignition of these light producing matrode from a high voltage source to any portion 10 teri-als has been accomplished, heretofore, by apof the lamp will bring about ignition. A solid plying heat from a filament, intensified if necesinside the envelope which may be ignited by heat sary by a fulminating compound, directly to this applied to the outside of the container will also flash material. perform as an ignition device.

The flash lamp to be described is a departure This inflammable gaseous mixture is com- 15 from the previous art in that ignition of flash posed of an inflammable gas or vapor with an material is brought about by a self-propagating oxygenous supporter of combustion. The inflame produced upon ignition of an inflammable flammable gas or vapor may be any of the comgaseous mixture. The ignition impulse is thus pounds ormixtures possessing the flame productransferred from the ignition device indirectly ing characteristic'with oxygen or the gaseous 20 to the flash material. Combustion of the flash oxides of nitrogen as the supporter of combusmaterial progresses from a multitude of points tion. The lighter paraflin hydrocarbons, some .and is aided by this flame. of which are present in natural gas, are suitable The flash material may be as foil, wire, powbecause of their stability.

der or similar form. Aluminum and magnesium For illustration a natural gas composed of apare adaptable as flash materials, though any solid proximately 78%methane, 18% ethane, 2% nitromay be used which will emit light upon combusgen, 1% illuminants, 0.8% oxygen, 0.2% carbon 131011 t Oxygen Speed O the flash is largely dioxide, is considered. A change in the inflama function of the fineness of these,materials. 1 mable gas will necesitate a change in the ratios The accompanying drawing shows a side view, and amounts of components which should be 30 partly in section, of a lamp embodying the prinpresent in the inflammable gaseous mixture; the

ciples of this invention. principle involved will remain the same. Experie In the figure, the sealed transparent envelope, ment indicates that the lower inflammable limit of (1), to which the usual base has been attached, this gas in oxygen or in oxygen-air mixtures is consists of a conventional glass bulb equipped approximately 5.5%, low total pressures requir- W t the Conventional Style Stem and exhaust ing an increase in this ratio for the production tube. A solid flash material, hereillustrated as of self-propagating fiama For example,

aluminum foil is held in the Upper Portion duction of the total pressure of a 6% mixture of g g g P by a i g this gas in oxygen enfeebles the flame, at 300 mm.

s 1e mg evice consis ing-o an as es os s cc of mercury and wlth spark 1gn1t1on the flame gg i g gg gggiggi gz gg fiz ig g gfi which is produced might better be described as a glow. This glow is noticeable at 200 mm. with an place by Support and 8% mixture and at so mm. with a 10% mixture.

rated in the stem press' A filament Wire Cooling eifect of the container temperature and f he foil b he sh ld' e, i i Separated mm t y t 18 mg devlc method of ignition affect these ratios to a small (4), is supported by the lead wires, (5a) and (5b), which'connect it electrically with the base extent in the conventional manner. The envelope is In flash lamp an mfiammable gaseous filled with an inflammable gaseous mixture of mm may-be adapted-t0 non'infiammability upon natural gas and oxygen t sub at,mospheric leakage of air into the envelope by limiting the 50 pressure. This inflammable gaseous mixture '7 at a d amounts of the s us omp ents contains an excess of available oxygen i. e. suffiwhich are p nt in h la p. F reat st adcient oxygen to combine with the natural gas vantage of this safety action the ratio of natural and an excess which will combine with the flash gas to oxygen Sh b as low as Possible d y t material. By omitting the metal filament, (3), insure ignition of the flash material under prac- 55 tical conditions; the amounts such that violation of the inflammable limit occurs before the added air renders the lamp explosive upon flring. Leakage is limited in that it may progress only until atmospheric pressure is reached inside the envelope, the partial .pressure of natural gas must he, therefore, less than 5.5% of atmospheric pressure for this leakage to produce non-inflammabil-- ity. Lamps constructed as per illustration were filled, for example, to 200 mm. with a 10% mixture of natural gas in oxygen, non-inflammability may be made to occur at a lower pressure by filling to a lower pressure for example, mm.

I claim: J

1. A flash lamp comprising in combination; a sealed transparent envelope; an ignition device withinsaidenvelope; an inflammable gaseousmix- -ture at sub-atmospheric pressure containing an lope; an ignition device within said envelope; 9.

solid material adapted to light emission upon combination with said excess oxygen, said ignition device initiating combustion of said inflammable gaseous mixture, and combustion of said inflammable gaseous mixture initiating combustion of,

said solid material.

3. A flash lamp comprising in combination; a

sealed transparent envelope; an inflammable gaseous mixture at subatmospheric pressure, said an ignition device within said envelope; a solid material adapted to light emission upon combination with said excess oxygen: a shielding device preventing direct ignition of said solid material by said ignition device, said ignition device initiating combustion of said inflammable gaseous mixture, and combustion of said inflammable gaseous mixture initiating combustion of said solid material.

4. A flash lamp embodying a sealed transparent envelope containing a gaseous mixture capable of producing a self-propagating flame upon ignition, said gaseous mixture containing an excess of available oxygen, said envelope containing also a solid material which will combine with said excess of available oxygen to produce light.

5. In a flash lamp having a gas-tight transparent envelope the combination; a solid combustible material adapted to light emission upon combustion with oxygen; an inflammable gaseous mixture at sub-atmospheric pressure, said gaseous mixture containing an excess of available oxygen and adapted, by virtue of ratio and amounts of components present, to non-inflammability upon addition of air'due to leakage of said envelope.

CHESHIRE JONES NICHOLS. 

